AMD Ryzen 9 7940HS analysis - Zen4 Phoenix is ideally as efficient as Apple

In this article, we have analyzed the new AMD Ryzen 9 7940HS' performance using synthetic benchmarks, as we do for our regular laptop reviews. Additionally, we have taken a look at its efficiency by measuring its power consumption during multiple benchmarks. To rule out varying screen types (and sizes) as influencing factors, we have connected the laptops to external monitors and switched off their internal displays. We have also compared the CPUs' power consumption in idle mode. We haven't gone into gaming benchmarks at this stage, as the range of graphics cards and TDP/TGP configurations is simply too wide.

First, let's take a look at single-core performance. For this, we have utilized different versions of Cinebench and Geekbench. In the comparison table, it has to be noted that Cinebench R15 and R20 had to be emulated on the Apple M2 chips and native benchmarks are not available for this processor. This had a slightly negative impact on its performance.

Single-core performance is typically a discipline in which AMD chips tend not to do too well - especially since Intel started using P-cores in last year's Alder Lake generation. The manufacturer was able to improve the performance with the introduction of their new Zen4 chips and on average we measured an improvement of 19 per cent compared to last year's Ryzen 9 6900HX and the Ryzen 7 7735HS (both chips are Zen3+, Rembrandt-R, 6 nm) - quite an impressive development. In the Cinebench tests, the new Ryzen 9 7940HS still had to admit defeat to the current Intel CPUs and was practically on the same level as last year's Core i7-12700H. In the Geekbench test, the AMD chip did considerably better - even beating the Lenovo Yoga Pro 7 14's Core i7-13700H and the ROG Zephyrus M16's Core i9-13900H. It came in only slightly behind both HX models.

In turn, looking at power consumption makes it obvious that this higher performance (or higher clock rate) has led to higher power consumption - both the AMD Ryzen 9 7940HS and Intel Core i7-13700H processors have a CPU package power of 23-24 watts and a core power of 21-22 watts. The old Zen3+ models such as the Ryzen 7 7735HS have a core power of only 16-16 watts, which means their single-core performance has got worse (-19 per cent) despite their improved performance. Apple's current M2 Pro SoC is still on a completely different level.

In the multi-core benchmarks, the Ryzen 9 7940HS left a good impression despite its fewer threads - its maximum power consumption of 65 watts means the processor was able to keep up with Intel's Alder Lake chips as well as the new Core i7-13700H. Those chips, however, can use over 100 watts at times. Compared to its predecessor, the Ryzen 9 6900HS, the new Zen4 chip in our test was on average 30 per cent faster. Compared to the Asus TUF A15's Ryzen 7 7735HS (comparable power limits), it was 25 per cent ahead in total.

Compared to the single-core tests, our multi-core benchmarks showed improved efficiency compared to the old Zen3+ processors - however, only compared to the HS models such as the Ryzen 7 7735HS. In addition, this is also dependent on power limits - its lead over the Lenovo Yoga Pro 7's 7735HS is minimal, but its efficiency rose by 30 per cent compared to the Asus TUF A15 (with the same TDP as the 7940HS). The old U series chips, such as the Ryzen 7 6800U (15-28 watts) are surprisingly more efficient. The Intel processors (Alder Lake and Raptor Lake) clearly lost out, the Ryzen 9 7945HX is more efficient (even though it has a higher consumption). In comparison: At 80 watts, the Ryzen 9 7940HS scored 18,044 points in the Cinebench R23 Multi test and the Ryzen 9 7945HX scored 31,000 points. 

Here, you can clearly see that the Ryzen 9 7940HS delivered better performance at all power limits than its direct competitor, the Intel Core i7-13700H. From 55 to 65, the curve already becomes much flatter, meaning efficiency started to decline. The Core i7-13700H's P-cores simply use a lot of energy to deliver such good performance levels. From 65 watts, the Intel chip was able to close the gap between it and the AMD chip considerably. 

It is interesting to take a look at how efficiencies fare with lower power limits. Our efficiency is calculated by dividing the achieved number of points by its consumption, namely the laptop's total consumption which we measured attached to an external monitor. This meant we got the following results for the Ryzen 9 7940HS:

Using lower power limits, we observed higher efficiency and at 45 watts, the new Ryzen 9 7940HS did about as well as the old Ryzen 7 6800U and the Apple M2 Max. At 35 watts, the new Zen4 chip did even better - almost as good as the Apple M2 Pro even. This shows that the new HS CPUs are happiest at 35-55 watts and it gives us great hope for the coming U series processors.